This invention relates to grain dryers and particularly grain dryers which are utilized for drying grain for use as seed.
When grains are harvested for use as seed for the following year, they are usually harvested at a moisture level of approximately 17%. However, these grains cannot be stored with the moisture level this high. Accordingly, it is necessary to dry these grains and bring down their moisture level to approximately 121/2% in order to permit the grain to be stored over the winter.
One type of grain dryer which has been utilized for this purpose is a continuous feed grain dryer having three vertically oriented compartments. The two outside compartments have open upper ends for receiving the grain. Within the two outside compartments are a plurality of ventilator tubes which are in communication with the central compartment within the dryer. Air is forced into the central compartment and out through the ventilator tubes into the two outside compartments. The air circulates through the grain and is picked up by a second set of ventilator tubes which carry the air outwardly through the outside walls of the grain dryer to the atmosphere. The grain works its way from the top of the grain dryer to the bottom. When the grain reaches the bottom its moisture level has been reduced to the desired level, and the grain is carried away. Grain is continuously fed through the top and is removed through the bottom of the grain dryer. PG,3
Several deficiencies have been encountered with presently known grain dryers such as the one described above. One deficiency is that there is not sufficient air moved through the grain to permit it to be dried adequately in a short period of time. The result is that the grain must move much more slowly through the grain dryer, thereby limiting the capacity of the grain dryer to accommodate grain as it is harvested.
Another deficiency of the above type of grain dryer is that the grain is not properly cooled prior to the time that it exits from the grain dryer. The air that is circulated through the grain during the drying process is usually heated, resulting in the grain being hot as it reaches the bottom of the grain dryer. However, the temperature of the grain must be reduced before it can be stored.
Another deficiency of the presently known grain dryers is the difficulty in providing an automatic system for feeding the grain to the dryer continuously without causing an overflow or a slack in the flow of grain.
Another deficiency of present grain dryers is the fact that only one air temperature is utilized as the grain progresses through the dryer. It would be desirable to have different temperatures at different levels, with the highest temperature being at the top and with the lowest temperature approximating the ambient air temperature at the bottom.
Therefore, a primary object of the present invention is the provision of an improved grain dryer.
A further object of the present invention is the provision of a grain dryer which introduces a high temperature air to the grain at the upper level of the dryer and which introduces air within approximately 10.degree. of the outside ambient temperature at the lower portion of the grain dryer.
A further object of the present invention is the provision of a grain dryer which will accommodate soybeans, corn, wheat, oats, and other types of grain without difficulty.
A further object of the present invention is the provision of a grain dryer which has a feed system utilizing an auger which is enclosed within a housing and which is positioned above the grain dryer.
A further object of the present invention is the provision of a grain dryer having a feed system which automatically turns on when the grain dryer is not full and which automatically turns off when the grain dryer is full.
A further object of the present invention is the provision of a grain dryer which improves the thoroughness with which the drying air is mixed with the grain.
A further object of the present invention is the provision of a grain dryer which can be constructed in a modular form which permits the adding on of additional length, height and volume to the grain dryer without detracting from the ability of the dryer to function efficiently.
A further object of the present invention is the provision of a device which is economical to manufacture, durable in use and efficient in operation.